arm/l2c: Convert to hotplug state machine

Install the callbacks via the state machine and let the core invoke
the callbacks on the already online CPUs.

Signed-off-by: Richard Cochran <rcochran@linutronix.de>
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Brad Mouring <brad.mouring@ni.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arm-kernel@lists.infradead.org
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160713153336.801270887@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/arm/mm/cache-l2x0.c

@@ -597,17 +597,16 @@ static void l2c310_configure(void __iomem *base)
 			      L310_POWER_CTRL);
 }
 
-static int l2c310_cpu_enable_flz(struct notifier_block *nb, unsigned long act, void *data)
+static int l2c310_starting_cpu(unsigned int cpu)
 {
-	switch (act & ~CPU_TASKS_FROZEN) {
-	case CPU_STARTING:
-		set_auxcr(get_auxcr() | BIT(3) | BIT(2) | BIT(1));
-		break;
-	case CPU_DYING:
-		set_auxcr(get_auxcr() & ~(BIT(3) | BIT(2) | BIT(1)));
-		break;
-	}
-	return NOTIFY_OK;
+	set_auxcr(get_auxcr() | BIT(3) | BIT(2) | BIT(1));
+	return 0;
+}
+
+static int l2c310_dying_cpu(unsigned int cpu)
+{
+	set_auxcr(get_auxcr() & ~(BIT(3) | BIT(2) | BIT(1)));
+	return 0;
 }
 
 static void __init l2c310_enable(void __iomem *base, unsigned num_lock)
@@ -678,10 +677,10 @@ static void __init l2c310_enable(void __iomem *base, unsigned num_lock)
 			power_ctrl & L310_STNDBY_MODE_EN ? "en" : "dis");
 	}
 
-	if (aux & L310_AUX_CTRL_FULL_LINE_ZERO) {
-		set_auxcr(get_auxcr() | BIT(3) | BIT(2) | BIT(1));
-		cpu_notifier(l2c310_cpu_enable_flz, 0);
-	}
+	if (aux & L310_AUX_CTRL_FULL_LINE_ZERO)
+		cpuhp_setup_state(CPUHP_AP_ARM_L2X0_STARTING,
+				  "AP_ARM_L2X0_STARTING", l2c310_starting_cpu,
+				  l2c310_dying_cpu);
 }
 
 static void __init l2c310_fixup(void __iomem *base, u32 cache_id,

include/linux/cpuhotplug.h

@@ -37,6 +37,7 @@ enum cpuhp_state {
 	CPUHP_AP_PERF_METAG_STARTING,
 	CPUHP_AP_ARM_VFP_STARTING,
 	CPUHP_AP_PERF_ARM_STARTING,
+	CPUHP_AP_ARM_L2X0_STARTING,
 	CPUHP_AP_ARM_ARCH_TIMER_STARTING,
 	CPUHP_AP_DUMMY_TIMER_STARTING,
 	CPUHP_AP_METAG_TIMER_STARTING,